The rapid development of worldwide adoption of PC Card technology has been due in large part to the standards efforts of the Personal Computer Memory Card International Association (PCMCIA). The PC Card standard defines a 68-pin interface between the peripheral cards and the socket into which it is inserted.
The PC Card standard provides physical specification for three types of cards, with additional provisions for extended cards (increased length). All three card types measure the same length and width, 85.6 mm and 54.0 mm respectively. The thicknesses are 3.3, 5.0 and 10.5 millimeters for the Type I, Type II and Type III cards respectively. Smaller cards can fit into larger sockets.
The card types each have features that fit the needs of different applications. Type I PC Cards are typically used for memory devices. Type II PC Cards are typically used for I/O devices such as data/fax modems (including wireless modems), pagers, LANs, and mass storage devices. Type III PC Cards are used for devices which components are thicker, such as rotating mass storage devices. Extended cards, those having longer lengths than that of the standard three types, allow for the addition of components that must remain outside the system for proper operation. A common example of such components is antennas for wireless modem applications.
A PC modem card can provide wireless communication capability to laptop notebook personal computers, hand held computers and any other host computer system having a PCMCIA-compatible interface. In order for a PC modem card to properly operate, the card must be connected to an antenna.
A conventional antenna arrangement utilizes extended cards. Inherently, these cards have longer lengths than the three PCMCIA standard types. For this reason, this arrangement is undesirable because conformity with the three PCMCIA standard types. Furthermore this arrangement is undesirable because such an extended card must extend beyond the housing of the host computer, regardless of whether the antenna is in use.
Another conventional antenna arrangement employs an antenna attached to a printed circuit board of a modem card. The problem with this arrangement, however, is that by attaching the antenna to the card the overall thickness of the card is increased. In the computer age, however, smaller is better, or in this case, thinner is better. Moreover, it is desirable to have an antenna/card design which conforms to the PCMCIA Card dimensional standards. Depending upon the PCMCIA card type, an arrangement with an antenna affixed on top of the circuit board may violate the standards.
In addition, modem cards are typically randomly oriented during use and, thus, suffer from multipath reflections and rotation of polarization. It is therefore desirable for the antenna connected to the modem card to be reorientated to adjust the polarization and to mitigate multipath reflections.
It is therefore evident that there exists a need in the art for a modem card antenna design which conforms to PCMCIA Card standards, does not require the antenna to be exposed from the host computer when not in use, and allows for freedom of antenna orientation to adjust the antenna polarization and to mitigate multipath reflections.